A 13-year-old boy who applied to a Hershey, Pa., boarding school told ABC News that it never crossed his mind he would be denied entry because he was HIV-positive.

"I thought I would get into the school, because of the type of student and person I am," he told ABC News in a written interview through his lawyer.

As a result of the school's decision, he added, "my life has turned into fear, anger, confusion and tears."

The school said today that its residential setting and the risk of sexual activity made the teen too much of a "threat."

The AIDS Law Project has filed suit on behalf of the boy, whose name is being withheld because of his age, on Wednesday in Philadelphia District Court, alleging that the Milton Hershey School violated the Americans with Disabilities Act, which includes HIV in its scope.

"This young man is a motivated, intelligent kid who poses no health risk to other students, but is being denied an educational opportunity because of ignorance and fear about HIV and AIDS," said Ronda Goldfein, the boy's lawyer.

"I don't see the direct threat," the boy told ABC News. "In my home we respect what my mother tells us to do. ... We come straight home from school, do homework, chores and do things as a family unit. Isn't that what Milton Hershey school is supposed to be about, but with a great educational environment? I guess not?!"

Connie McNamara, spokesperson for Milton Hershey, told ABCNews.com the school carefully evaluated the situation and the needs of its 1,850 students, which span from pre-kindergarten to 12th grade.

"We had to balance his rights and interests with our obligation to provide for the health and safety of other students," she said. "And this meets a direct threat."

McNamara knows well that coughing, hugging, and public restrooms won't cause someone to get HIV.

She said the school was most worried the boy would have sex -- if not now, at some point in his future years at the school, where students in groups of 10 to 12 live together in on-campus housing.

"Our kids are no different than teenagers anywhere else," she said. "Despite encouraging abstinence, we can not be 100 percent certain our kids are not engaging in sexual activity."

Even making sure the boy and students were educated on how HIV is transmitted wasn't enough for the school to grant the teen admission.

The idea that anyone could be denied entry based on a disability is astounding, said Arthur Caplan, director of the Pennsylvania Center for Bioethics.

"This notion that you can't put him in residential housing at a school because he is a vector of death is a throwback to 1987, when people were worried you couldn't mainstream children in any school," he said. "It sets back what we know to be true about the disease."

Caplan suggested the school use this as a teaching opportunity to educate students about HIV.

"I'd like to see the school hold a seminar," said Caplan. "And if the school isn't going to do the right thing, students need to confront the administration."

Even the school seemed a bit conflicted during the application process. McNamara provided ABC News with a court document the school planned to file before the lawsuit, asking a judge to weigh in and make sure they were within the bounds of the law.

"We looked at the law and our unique program and made the best decision we could," she said. "Our heart goes out to this young man."